This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Large-scale tissue engineering requires tissues with pre-developed blood vessels. The vasculature in the engineered tissue must connect with host vessels. How this occurs and how it might be optimized are poorly understood. To address this knowledge gap, we propose an interdisciplinary collaborative effort amongst faculty with expertise in tissue engineering and biophotonics. The overall objective is to develop a real-time imaging approach to determine the time course over which the engineered tissue becomes perfused with blood after implantation in a live animal. Our central hypothesis is that perfusion will occur within 48 h after implantation. This hypothesis will be tested by pursuing two specific aims: 1) Develop a robust animal model which enables real-time visualization of host and implant microvasculature;and 2) Establish the time course of perfusion dynamics within the host and implant microvasculature. Under the first aim, we will develop a suitable animal model that enables real-time imaging of the host and implant microvasculature. Under the second aim, we will measure blood flow and hemoglobin oxygen saturation imaging of the window chamber over a period of up to 28 days post-surgery. The proposed research is innovative, because it will establish a new method to study quantitative changes in the vascular network and the biological signals which govern these changes, in both engineered tissue implants and the host tissue. The proposed research is significant, because it will enable discovery of an optimal strategy to engineer thick tissue implants with maximal clinical utility in applications of regenerative medicine.